Reinforced roll



Jan. 4, 1966 w. c. HILL. JR.. ETAL REINFORCED ROLL 3 Sheets-Sheet 1 Filed July 31, 1962 INVENTORS WALTER c. HILL, JR.

WINFIELD C. TWITCHELL ywcaiw ATTORNEY Jan. 4, 1966 w. c. HILL, JR. ETAL 3,

REINFORCED ROLL 3 Sheets-Sheet 2 Filed July 31, 1962 INVENTORS W ER C-HILL, JR. W ELD CTWITCHELL Wan/7 ATTORNEY Jan. 4, 1966 w. c. HILL, JR.. ETAL 3,227,857

REINFORCED ROLL 5 Sheets-Sheet 5 Filed July 31, 1962 INVENTOR5 WALTER C. HILL, JR. W/NF/ELD C. TW/TCHELL BY WM y. w 52,1

ATTORNEY United States Patent Office 3,227,857 Patented Jan. 4, 1966 3,227,857 REINFORCED ROLL Walter C. Hill, Jr., and Winfield C. Twitchell, Wilmington, Del., assiguors to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Filed July 31, 1962, Ser. No. 213,747 Claims. (Cl. 219469) This invention relates to a rotary roll, and particularly to a rotary roll of low mass and high strength obtained by providing internal reinforcement integral therewith.

The manufacture of polymeric textile yarns, strands and films frequently requires the use of high speed heated rolls over which the product is passed to thereby heat, cure, stretch, or otherwise process it by direct, and more or less sustained, contact with the outside surfaces of the rolls. Often the running product breaks and winds on the rolls, necessitating shut-down of the equipment until the wrapped material can be removed, discarded to waste and the free end rethreaded through the apparatus preparatory to resumption of manufacture. The rolls run at relatively high rotational speeds and it is advantageous to reduce their masses as much as practicable to correspondingly reduce the time intervals required for shutdown and startup. Thus, it is advantageous to use aluminum or aluminum alloys, which also possess a high heat conductivity, as a preferred material of construction, additionally designing the roll as an annular cylinder to further reduce the total mass.

However, aluminum and its most economical alloys have the serious disadvantage of low strengths at even relatively moderately high temperatures, such as 400 F., for example, and thus cannot withstand the centrifugal stresses of high rotation. In addition, polymeric yarn and strip wraps impose high radially inward squeeze stresses, which tend to distort the rolls out of precise cylindrical shape, and aluminum and its alloys do not possess enough compressive strength, particularly at high temperatures, to withstand these stresses satisfactorily.

An object of this invention is to provide an improved heated reinforced rotary roll fabricated from aluminum or its alloys possessed of high strength, relatively low mass, and a high capability of withstanding both centrifugal stresses imposed by high speed rotation and inwardly directed squeeze stresses imposed by accidental product wraps. Another object of this invention is to provide a rotary roll for high temperature service which is relatively economical to fabricate, and utilizes readily obtainable shapes of steel reinforcing for low cost and high strength. The manner in which these and other objects of this invention are attained will become clear from the following detailed description and the drawings, in which:

FIG. 1 is a side-e1evational, cross-sectional partially schematic representation of a preferred embodiment of this invention utilizing a helical steel pipe coil as the reinforcing channelway,

FIG. 2 is an end view of the construction of FIG. 1 looking in the direction of the arrows 2--2,

FIG. 3 is a schematic representation in partial half longitudinal section of a second embodiment of this invention utilizing stayed, concentric, corrugated-wall steel pipes as the reinforcing channelway,

FIG. 4 is a section taken on line 4-4, FIG. 3,

FIG. 5 is a side elevation of a length of steel pipe prior to its winding on a mandrel to give a helical pipe coil such as that of FIG. 1, and

FIG. 6 is a side elevation view of the completely wound coil formed from the steel pipe length of FIG. 5.

Generally, this invention comprises a rotary roll of cylindrical outside profile fabricated from aluminum or aluminum alloys of relatively high heat conductivity provided with a generally cylindrically bounded steel channelway coextensive in length with the working length of the roll and embedded internally of the roll coaxial therewith during the casting of the roll, the channelway housing heating means adapted to heat the roll by conduction through the wall of the channelway into the aluminumrich material in which the channelway is embedded.

Referring to FIG. 1, this embodiment of roll is designed for cantilever support from a drive source indicated generally at 10, which is provided with a tapered hollow steel drive shaft 11. The inboard end of the roll, indicated generaly at 17, carries a cast-in-place steel sleeve.

12, of matching taper with shaft 11, thereby permitting firm draw-up of the roll on the shaft by tightening of threaded nut 15 on the companionately threaded outboard end of drive shaft 11, a steel washer 16 being interposed between nut and sleeve.

The roll itself consists of a generally annular aluminum or aluminum alloy body, arround the outside surface 21 of which yarn or other running material to be heat-treated is passed. The inboard end of the roll is reduced in diameter to form a hub 18. The exterior of sleeve 12 is preferably grooved circumferentially at 19, and is also well-roughened by knurling, so as to achieve a tight bond with the interior of hub 18 during the casting attachment thereto, thus locking the roll fixedly on sleeve 12.

Structural strength is imparted to the roll, according to this invention, by embedding therein, during the casting of body 17, a steel channelway which, in the embodiment of FIGS. 1 and 2, is a helical coil indicated somewhat schematically at 22. Coil 22 is mounted coaxially of the roll and can typically be fabricated from seamless, 0.25" OD. x 0.02 wall steel tubing having an outside diameter approximately 25% of the wall thickness of the annular wall of roll 17. The geometric cylinder generally bounding the coil is preferably disposed about 45% of the thickness of the annular roll wall radially outwards from the inside periphery of the roll. Successive turns of coil 22 are preferably spaced apart about one tube radius, thus permitting cast-in-place aluminum metal disposition around the entire peripheral surface of the pipe channelway. Precise spacing of individual coil turns with respect to one another can be obtained by the use of light steel spacer combs 24 recessed along the outer edges to receive snugly each coil turn which can, if desired, be tack-welded in place to make a unitary assembly. Three combs 24 evenly spaced circumferentially of the coil degrees apart provide high structural rigidity for the steel reinforcing structure.

Coil 22 of the embodiment of FIGS. 1 and 2 is preferably wound from the two separate halves of a single length of straight tubing in alternation, so that single helical turns formed up from the stock of one half have each interposed therewith single helical turns formed up from the stock of the other half. Referring to FIGS. 5 and 6, this is accomplished by first making a reverse bend approximately at midlength of a unitary piece of tubing, one end of which is arbitrarily referred to as end A whereas the other is denoted end B. Then, each end is helically wound in alternation on a common mandrel, so that individual coils formed from A are separated one from another by individual coils of B. The reverse bend end by which coil A connects with coil B is embedded within the heavy metal end of the roll adjacent hub 13, thereby providing an additional heat supply to this point from which heat conduction losses via shaft 11 occur into drive source 10 and its contacting environment. With this construction both ends of the coil, 22a and 221), are brought out coparallel with the axis of shaft 11 at the outboard end of roll 17. The channel-way provided by coil 22 houses the electrical-resistance heating element which, in this instance, constitutes the heating means for the roll, this being a conventional wire design electrically insulated from the interior of coil 22 by packing centrally within metal oxide powders having also high thermal resistance. The open coil ends are sealed off with washers 25a and 25b, provided with electrically insulating conductor-spacing bonnets drilled axially to receive leads 26a and Zeb, respectively, making firm electrical contact with the two ends of the heating element.

As shown in FIG. I, particularly, the outboard end of roll 17 is provided with a dished head 29 attached to the roll by screws and provided with a centrally disposed electrical conduit length 39. Conduit 30 has its inboard end slidably received within a recess provided in the outboard end of shaft lil, thereby accommodating for thermal expansion and contraction of the roll in the course of heating-cooling cycles. Electrical connections with the heat ing power source, not shown, are made via leads 31a and 31b run through conduit 3t and the drilled bore of shaft 11. The electrical circuit with the resistance heating unit is preferably completed through fusible conductive links 32a and 32b, safeguarding against electrical overloads destructive to the roll and its appurtenances. If desired, temperature-measuring thermocouples can be readily provided, that shown with leads 35 being connected in circuit via extension conductors led off through conduit 3&9 and the bore of shaft ill to a suitable recorder, whereas that provided with leads 36 is a spare adapted to be connected in substitution for the other thermocouple should conditions ever require. All electrical connections are shielded from the outside by cover 37 (removed in FIG. 2), fitting within a shouldered recess in the outboard end of roll 17 and attached thereto by screws. External electrical connections to power source and temperature recorder are made in conventional manner through slip rings or similar devices, such as taught in US. Patents 1,496,356 and 2,526,906, for example.

Reinforced rolls according to this invention are fabricated by placing the steel insert parts, such as sleeve 12 and coil 22 together with its assembled spacer combs 2-2 in their proper positions within the mold, and then pouring the molten aluminum, or aluminum alloy, into the mold to the fullness point. It is usually most convenient to emplace the resistance heating wire element within coil 22 before the casting operation, and this applies also to the thermocouple wire pairs, which are preferably stretchmounted in the appropriate locations in the mold beforehand and then covered with the molten aluminum. While electrical resistance elements are convenient heating means in many installations, the design of this invention is not limited thereto. Thus, it is entirely feasible to employ steam, heated fluids, both gaseous and liquid, or a wide variety of other means for heating, since the channelway afforded by coil 22 is completely closed and can be readily connected in flow circuit with fluid-supply connections passed through the bore of shaft Jill and conduit 34 A practicable design would be to introduce the hot fluid through a conventional, axially aligned, stationary-to-rotating member coupling of the general type taught in US. Patent 2,455,539 disposed at the left-hand end of the apparatus as seen in FIG. 1, and exhaust the spent fluid via an identical coupling disposed at the right-hand end of the apparatus.

One design of aluminum roll constructed as hereinbefore described had a working lengthof about 10.25", a diameter of 6.50" and an emplaced reinforcing coil 22 consisting of 17%. turns of 0.25" outside diameter tubing made up into a 5.15" outside diameter helix 22 as reinforcing channelway. This roll gave excellent service in a high speed yarn-drawing application requiring close temperature maintenance at a level of about 400 F., and frequent abrupt starts and stops to accommodate manufacturing process procedures. Frevious experience with unreinforced aluminum rolls had shown them to be completely inadequate for this particular service, due to deformation of the roll under both outwardly acting centrifugal stresses and the inwardly-applied compressive loads imposed by yarn wind-on.

Referring to FIGS. 3 and 4, a second embodiment of this invention employs as reinforcing structure a pair of concentrically arranged corrugated steel tubes 42 and 43 spaced one from another radially by weld attachment to the ends of spokes 44, the space therebetween constituting a substantially unobstructed channelway 45. The ends of the channelway are sealed off by annular steel plates, not shown, preferably welded in place, which can be provided with suitable nipples or other connections for reception of the roll heating means, which are preferably assembled in place within any electrical insulation employed prior to the casting of the roll. Again, an annular design of roll 17' is shown, as this is usually preferred because of reduced mass.

The spokes 4-4 can conveniently be made integral with bore-aligned hubs 47, which provide support for conduit 30 corresponding to leadway conduit 30 of FIG. 1. The rest of the construction is identical with that of FIGS 1 and 2.

In some respects the design of FIGS. 3 and 4 is preferred, because of the additional heating surface presented by the steel conduits to the surrounding cast-on aluminum, the strength and mass attributes of each of the em bodiments being approximately equal for the purposes.

In general, the reinforced roll design of this invention accomplishes a compromise as to two principal requirements: (1) even heat distribution to the roll, and (2) high strength and form stability overall.

From the foregoing, it is apparent that this invention can be modified in numerous respects without departure from its essential spirit, and it is intended to be limited only within the scope of the appended claims.

What is claimed is:

l. A rotary roll of cylindrical outside profile fabricated from a casting of one of the group consisting of aluminum and aluminum alloys of relatively high heat conductivity provided with a generally cylindrically bounded unitary circumferentially formed steel channelway coextensive in length with the length of said roll throughout which substantially uniform temperature maintenance is desired and disposed internally of said roll coaxial therewith, said channelway being provided with heating means adapted to heat said roll by conduction through the walls of said channelway into the mass of said roll within which said channelway is disposed.

2. A rotary roll of cylindrical outside profile fabricated from a casting of one of the group consisting of aluminum and aluminum alloys of relatively high heat conductivity provided with a generally cylindrically bounded unitary circumferentially formed steel channelway coextensive in length with the length of said roll throughout which substantially uniform temperature maintenance is desired and disposed internally of said roll coaxial therewith, said channelway being defined by a pair of concentric corrugated-wall interstayed steel tubes separated one from another by an annular space provided with heating means adapted to heat said roll by conduction through the walls of said cor-ru'bated steel tubes.

3. A rotary roll of cylindrical outside profile fabricated from a casting of one of the group consisting of aluminum and aluminum alloys of relatively high heat conductivity according to claim 2 wherein said pair of corrugated-wall steel tubes are interstayed by a multiplicity of radial spokes disposed at different planes transverse said roll and staged lengthwise thereof.

4. A rotary roll of cylindrical outside profile fabricated from a casting of one of the group consisting of aluminum and aluminum alloys of relatively high heat conductivity provided with a helical steel coil channelway coextensive in length with the length of said roll throughout which substantially uniform temperature maintenance is desired and disposed internally of said roll and coaxial therewith, said steel coil channelway being provided with heating means adapted to heat said roll by conduction through the wall of said steel coil channelway into the mass of said roll within which said steel coil is disposed.

5. A rotary roll of cylindrical outside profile fabricated from a casting of one of the group consisting of aluminum and aluminum alloys of relatively high heat conductivity according to claim 4 wherein said heating means consists of electrical resistance heating elements disposed throughout the length of said steel coil channelway and electrically insulated therefrom by thermally resistant insulation material.

References Cited by the Examiner UNITED STATES PATENTS 11/1922 Lehman 22-58 X 6/1928 Miller 165-89 2/1939 Harris ll56 X 4/1949 Boling et al. 169 X 12/1951 Gunther 219-1918 X FOREIGN PATENTS 2/1957 Germany.

RICHARD M. WOOD, Primary Examiner.

JOSEPH D. BEIN, WALTER A. SCHEEL, Examiners. 

1. A ROTARY ROLL OF CYLINDRICAL OUTSIDE PROFILE FABRICATED FROM A CASTING OF ONE OF THE GROUP CONSISTING OF ALUMINUM AND ALUMINUM ALLOYS OF RELATIVELY HIGH HEAT CONDUCTIVITY PROVIDED WITH A GENERALLY CYLINDRICALLY BOUNDED UNITARY CIRCUFERENTIALLY FORMED STEEL CHANNELWAY COEXTENSIVE IN LENGTH WITH THE LENGTH OF SAID ROLL THROUGHOUT WHICH SUBSTANTIALLY UNIFORM TEMPERATURE MAINTENANCE IS DESIRED AND DISPOSED INTERNALLY OF SAID ROLL COAXIAL THEREWITH, SAID CHANNELWAY BEING PROVIDED WITH HEATING MEANS ADAPTED TO HEAT SAID ROLL BY CONDUCTION THROUGH THE WALLS OF SAID CHANNELWAY INTO THE MASS OF SAID ROLL WITHIN WHICH CHANNELWAY IS DISPOSED. 